Editing Alder (section)

==Phylogeny==

=== Classification ===
{{multiple image
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| caption1          = A young bull moose [[Browsing (herbivory)|browsing]] on Alnus in [[Homer, Alaska]] in 2010
| image2            = Big alders.jpg
| caption2          = The same spot from the same angle in 2021, the plants are now about {{convert|12-15|feet|order=flip}} in height
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The genus is divided into three subgenera:

==== Subgenus ''Alnus'' ====
[[File:Alnus incana rugosa leaves.jpg|right|thumb|Speckled alder (''Alnus incana'' subsp. ''rugosa'')—leaves]]
[[File:Alnus serrulata leaves.jpg|right|thumb|Leaves of the tag alder]]

Trees with stalked shoot buds, male and female catkins produced in autumn (fall) but stay closed over winter, pollinating in late winter or early spring, about 15–25 species, including:

{{Div col}}
* ''[[Alnus acuminata]]'' {{small|Kunth}} 
** subsp. ''acuminata'' {{small|Kunth}}
** subsp. ''arguta'' {{small|(Schltdl.) Furlow}}
** subsp. ''glabrata'' {{small|(Fernald) Furlow}}
* ''[[Alnus cordata]]''  {{small|(Loisel.) Duby}} 
* ''[[Alnus cremastogyne]]'' {{small|Burkill}} 
* ''[[Alnus firma]]'' {{small|Siebold & Zucc.}} 
* ''[[Alnus glutinosa]]'' {{small|(L.) Gaertn.}} 
** subsp. ''barbata'' {{small|(C.A.Mey.) Yalt.}}
** subsp. ''glutinosa'' {{small|(L.) Gaertn.}}
** subsp. ''incisa'' {{small|(Willd.) Regel}}
** subsp. ''laciniata'' {{small|(Willd.) Regel}}
* ''[[Alnus hirsuta]]'' {{small|(Spach) Rupr.}} 
* ''[[Alnus incana]]'' {{small|(L.) Moench}}
** subsp. ''incana'' {{small|(L.) Moench}}
** subsp. ''kolaensis'' {{small|(Orlova) Á.Löve & D.Löve}}
** subsp. ''rugosa'' {{small|(Du Roi) R.T.Clausen}}
** subsp. ''tenuifolia'' {{small|(Nutt.) Breitung}}
* ''[[Alnus japonica]]'' {{small|(Thunb.) Steud.}} 
* ''[[Alnus jorullensis]]'' {{small|Kunth}} 
** subsp. ''lutea'' {{small|Furlow}}	
** subsp. ''jorullensis'' {{small|Kunth}}
* ''[[Alnus lusitanica]]'' {{small|Vít, Douda, & Mandák}}<ref name="Vít-2017">{{cite journal |last1=Vít |first1=Petr |last2=Douda |first2=Jan |last3=Krak |first3=Karol |last4=Havrdová |first4=Alena |last5=Mandák |first5=Bohumil |year=2017 |title=Two new polyploid species closely related to ''Alnus glutinosa'' in Europe and North Africa – an analysis based on morphometry, karyology, flow cytometry and microsatellites |journal=Taxon |volume=66 |issue=3 |pages=567–583 |doi=10.12705/663.4}}</ref>
* ''[[Alnus matsumurae]]'' {{small|Callier}}
* ''[[Alnus nepalensis]]'' {{small|D.Don}} 
* ''[[Alnus oblongifolia]]'' {{small|Torr.}}
* ''[[Alnus orientalis]]'' {{small|Decne.}}
* ''[[Alnus rhombifolia]]'' {{small|Nutt.}} 
* ''[[Alnus rohlenae]]'' {{small|Vít, Douda, & Mandák}}<ref name="Vít-2017" />
* ''[[Alnus rubra]]'' {{small|Bong.}}
* ''[[Alnus serrulata]]''  {{small|(Aiton) Willd.}}
* ''[[Alnus subcordata]]''  {{small|C.A.Mey.}}
* ''[[Alnus tenuifolia]]'' {{small|Nutt.}}
* ''[[Alnus trabeculosa]]'' {{small|Hand.-Mazz.}}
{{Div col end}}

==== Subgenus ''Clethropsis'' ====
Trees or shrubs with stalked shoot buds, male and female catkins produced in autumn (fall) and expanding and pollinating then, three species:

* ''[[Alnus formosana]]'' {{small|(Burkill) Makino}}
* ''[[Alnus maritima]]'' {{small|(Marshall) Muhl. ex Nutt.}}
* ''[[Alnus nitida]]'' {{small|(Spach) Endl.}}

==== Subgenus ''Alnobetula'' ====
[[File:Alnus-viridis-leaves.JPG|right|thumb|Green alder (''Alnus viridis'')]]

Shrubs with shoot buds not stalked, male and female catkins produced in late spring (after leaves appear) and expanding and pollinating then, one to four species:

{{Div col}}
* ''[[Alnus alnobetula]]'' {{small|(Ehrh.) K.Koch}} (synonym-''Alnus viridis'')
** subsp. ''alnobetula'' {{small|(Ehrh.) K.Koch}}
** subsp. ''crispa'' {{small|(Aiton) Raus}}
** subsp. ''fruticosa'' {{small|(Rupr.) Raus}}
** subsp. ''sinuata'' {{small|(Regel) Raus}}
** subsp. ''suaveolens'' {{small|(Req.) Lambinon & Kerguélen}}
* ''[[Alnus firma]]'' {{small|Siebold & Zucc.}} 
* ''[[Alnus mandshurica]]'' {{small|(Callier) Hand.-Mazz.}}
* ''[[Alnus maximowiczii]]'' {{small|Callier}} 
* ''[[Alnus pendula]]'' {{small| Matsum.}} 
* ''[[Alnus sieboldiana]]'' {{small| Matsum.}} 
{{div col end}}

==== Not assigned to a subgenus ====
{{div col}}
* ''[[Alnus fauriei]]'' {{small|H.Lév. & Vaniot}} 
* ''[[Alnus ferdinandi-coburgii]]'' {{small|C.K.Schneid.}} 
* ''[[Alnus glutipes]]'' {{small|(Jarm. ex Czerpek) Vorosch.}}
* ''[[Alnus hakkodensis]]'' {{small|Hayashi}} 
* ''[[Alnus henryi]]'' {{small|C.K.Schneid.}}
* ''[[Alnus lanata]]'' {{small|Duthie ex Bean}} 
* ''[[Alnus mairei]]'' {{small|H.Lév.}} 
* ''[[Alnus paniculata]]'' {{small|Nakai}} 
* ''[[Alnus serrulatoides]]'' {{small|Callier}}
* ''[[Alnus vermicularis]]'' {{small|Nakai}}
{{div col end}}

==== Species names with uncertain taxonomic status ====
The status of the following species is unresolved:{{citation needed|date=October 2024}}

{{Div col|colwidth=300px}}
* ''Alnus balatonialis'' {{small|Borbás}}
* ''Alnus cuneata'' {{small|Geyer ex Walp.}}
* ''Alnus dimitrovii'' {{small|Jordanov & Kitanov}}
* ''Alnus djavanshirii'' {{small|H.Zare}} – Iran
* ''Alnus dolichocarpa'' {{small|H.Zare, Amini & Assadi}} – Iran
* ''Alnus figerti'' {{small|Callier}}
* ''Alnus frangula'' {{small|L. ex Huth}}
* ''Alnus gigantea'' {{small|Nakai}}
* ''Alnus glandulosa'' {{small|Sarg.}}
* ''Alnus henedae'' {{small|Sugim.}}
* ''Alnus hybrida'' {{small|Rchb.}}
* ''Alnus laciniata'' {{small|Ehrh.}}
* ''Alnus lobata'' {{small|Nyman}}
* ''Alnus microphylla'' {{small|Arv.-Touv.}}
* ''Alnus obtusifolia'' {{small|Mert. ex Regel}}
* ''Alnus oxyacantha'' {{small|Lavalle}}
* ''Alnus subrotunda'' {{small|Desf.}}
* ''Alnus vilmoriana'' {{small|Lebas}}
* ''Alnus washingtonia'' {{small|Wetzel}}
{{Div col end}}

==== Hybrids ====
[[File:AlnusXspaethii.jpg|thumb|upright|''[[Alnus x spaethii|Alnus × spaethii]]'']]

The following hybrids have been described:<ref name="PlantList">{{cite web |date=September 2013 |title=The Plant List entry for ''Alnus'' |url=http://www.theplantlist.org/1.1/browse/A/Betulaceae/Alnus/ |access-date=14 December 2020 |website=[[The Plant List]], v.1.1 |publisher=[[Royal Botanic Gardens, Kew]] and the [[Missouri Botanical Garden]]}}</ref><ref name="Govaerts-2017">{{cite web |author=Govaerts R |title=''Alnus'' Mill. |url=https://powo.science.kew.org/taxon/urn:lsid:ipni.org:names:30000643-2 |access-date=14 December 2020 |website=Plants of the World Online |publisher=Board of Trustees of the Royal Botanic Gardens, Kew}}</ref>

{{Div col}}
* ''[[Alnus × elliptica]]'' {{small|Req.}} (''A. cordata'' × ''A. glutinosa'')
* ''[[Alnus × fallacina]]''  {{small|Callier}} (''A. incana'' subsp. ''rugosa'' × ''A. serrulata'')
* ''[[Alnus × hanedae]]'' {{small|Suyinata}} (''A. firma'' × ''A. sieboldiana'')
* ''[[Alnus × hosoii]]'' {{small|Mizush.}} (''A. maximowiczii'' × ''A. pendula'')
* ''[[Alnus × mayrii]]'' {{small|Callier}} (''A. hirsuta'' × ''A. japonica'')
* ''[[Alnus × peculiaris]]'' {{small|Hiyama}} (''A. firma'' × ''A. pendula'')
* ''[[Alnus × pubescens]]'' {{small|Tausch.}} (''A. glutinosa'' × ''A. incana'')
* ''[[Alnus × suginoi]]'' {{small|Sugim.}}
{{Div col end}} 

The status of the following hybrids is unresolved:<ref name="PlantList" />

{{Div col|colwidth=300px}}
* ''Alnus'' × ''aschersoniana'' {{small|Callier}}
* ''Alnus'' × ''koehnei'' {{small|Callier}}
* ''Alnus'' × ''ljungeri'' {{small|Murai}}
* ''Alnus'' × ''purpusii'' {{small|Callier}}
* ''Alnus'' × ''silesiaca'' {{small|Fiek}}
* ''Alnus'' × ''spaethii'' {{small|Callier}} (''A. japonica'' × ''A. subcordata'')
{{Div col end}}

===Fossil record===
The oldest fossil pollen that can be identified as ''Alnus'' is from northern [[Bohemia]], dating to the late [[Paleocene]], around 58 million years ago.<ref>{{Cite journal |last1=Yang |first1=Xiao-Yue |last2=Wang |first2=Ze-Fu |last3=Luo |first3=Wen-Chun |last4=Guo |first4=Xin-Yi |last5=Zhang |first5=Cai-Hua |last6=Liu |first6=Jian-Quan |last7=Ren |first7=Guang-Peng |date=September 2019 |title=Plastomes of Betulaceae and phylogenetic implications |url=https://onlinelibrary.wiley.com/doi/10.1111/jse.12479 |journal=Journal of Systematics and Evolution |language=en |volume=57 |issue=5 |pages=508–518 |doi=10.1111/jse.12479 |issn=1674-4918 |s2cid=91509152}}</ref>

{{Div col |colwidth=50em}}
* †''[[Alnus fairi]]'' {{small|([[Frank Knowlton|Knowlton]]) Wolfe, 1966}} - Miocene; Western North America<ref name="Wolfe-1966">{{cite report |last1=Wolfe |first1=J.A. |year=1966 |title=Tertiary plants from the Cook Inlet region, Alaska |series= Professional Paper |publisher=United States Geological Survey |volume=398B |pages=1–32  |doi=10.3133/pp398B |doi-access=free }}</ref>
* [[Extinction|†]]''[[Alnus heterodonta]]'' {{small|(Newberry) Meyer & Manchester 1987}} – Oligocene; Fossil, Oregon
* †''[[Alnus hollandiana]]'' {{small|Jennings, 1920}} - Miocene; Western North America<ref name="Chaney-1959">{{cite book |last1=Chaney |first1=R. |last2=Axelrod |first2=D. |year=1959 |title=Miocene Floras of the Columbia Plateau: Part II. Systematic Considerations, by Ralph W. Chaney and Daniel I. Axelrod |publisher= Carnegie Institution of Washington |pages=1–226}}{{HathiTrust Catalog|uc1.c099384505|Miocene Floras of the Columbia Plateau}}</ref>
* †''[[Alnus largei]]'' {{small|([[Frank Knowlton|Knowlton]]) Wolfe, 1966}} - Miocene; Western North America<ref name="Wolfe-1966"/>
* †''[[Alnus parvifolia]]'' {{small|([[Edward W. Berry|Berry]]) [[Jack A. Wolfe|Wolfe]] & [[Wesley Wehr|Wehr]], 1987}} - Ypresian; [[Eocene Okanagan Highlands|Okanagan Highlands]]<ref name="Wolfe-1987">{{cite report |last1=Wolfe |first1=J. A. |last2= Wehr |first2=W. C. |year=1987 |title=Middle Eocene dicotyledonous plants from Republic, northeastern Washington |series= Bulletin |publisher=United States Geological Survey |volume=1597 |pages=1–25  |doi=10.3133/b1597 |doi-access=free }}</ref>
* †''[[Alnus relatus]]'' {{small|(Knowlton) [[Roland W. Brown|Brown]], 1937}} - Miocene; Western North America<ref name="Wolfe-1966"/>
{{Div col end}}

=== Etymology ===
The common name ''alder'' evolved from the Old English word ''alor'', which in turn is derived from [[Proto-Germanic]] root ''aliso''.<ref name="Harper">{{cite web |last=Harper |first=Douglas |title=alder {{!}} Etymology, origin and meaning of alder by etymonline |url=https://www.etymonline.com/word/alder#etymonline_v_8122 |access-date=22 March 2022 |website=[[Online Etymology Dictionary]]}}</ref> The generic name ''Alnus'' is the equivalent [[Latin]] name, from whence French ''aulne'' and Spanish ''Alamo'' (Spanish term for "[[Populus|poplar]]").<ref name="Harper" />